Hospitalized ventilated patients and patients that require emergent intubation (crush induction) are at increase risk for reflux of gastroesophageal contents. These populations are at risk for longer Length of Staying (LOS) or dying, not only from their critical illness but also from secondary processes such as nosocomial infection. Pneumonia is the second most common nosocomial infection in critically ill patients, affecting 27% of all critically ill patients [1], and is responsible for almost half of the infections in critically ill patients in Europe [2]. Eighty-six percent of nosocomial pneumonias are associated with mechanical ventilation and are termed ventilator-associated pneumonia (VAP). Between 250,000 and 300,000 cases per year occur in the United States alone, which is an incidence rate of 5 to 10 cases per 1,000 hospital admissions [3]. An independent contribution to mortality conferred by ventilator-associated pneumonia was recently suggested [4]. The mortality attributable to VAP has been reported to be as high as 50% [5]. Ventilator-associated pneumonia causes substantial morbidity by increasing the duration of mechanical ventilation and intensive care unit stay [6].
Beyond mortality, the economics of VAP include increased intensive care unit (ICU) LOS from 4 to 13 days, and incremental costs associated with VAP have been estimated at between $5,000 and $20,000 per diagnosis [7].
A growing body of evidence suggests that, in the presence of a functional gut, nutrition should be administered through the enteral route largely because of the morbidity associated with other modes of feeding. Furthermore, enteral alimentation is currently the most widely used modality for providing nutrition support in the ICU [8]. Favorable effects of enteral feeding include better substrate utilization, prevention of mucosal atrophy, and preservation of gut flora, integrity, and immune competence [9]. Therefore, there has been an increased interest among physicians to feed patients through the enteral route as soon as possible. Previous studies looking at critically ill patients with abdominal surgery, hip fracture, burn, and trauma demonstrated beneficial effects of early enteral feeding [10]. However, a report from critically ill medical patients suggested that early feeding to satisfy the patient's nutritive needs resulted in more harm and was associated with greater infectious complications [11].
In the pathogenesis of VAP, bacterial colonization of the oral cavity and subsequent aspiration of oropharyngeal fluids along the endotracheal tube are pivotal and should be prevented [12]. However, infectious hazards, tissue injury, and aspiration associated with placement and maintenance of orogastric and nasogastric tubes used for the delivery of enteral nutrition suggest that not all patients benefit of adequate preventive procedures. Bacterial colonization of the stomach and gastroesophageal aspiration is mainstay in the pathogenesis of VAP [13]. Gastroesophageal aspiration is facilitated by the presence of a nasogastric tube and a supine body position [14]. Experimental studies with radioactive-labeled enteral feeding indeed suggested that endotracheal aspiration of gastric contents occurred more frequently when patients were placed in supine rather than semi recumbent position [15]. On the basis of these findings, the Centers for Disease Control and Prevention advised treatment of mechanically ventilated patients in a semi recumbent position as a VAP-preventive measure [16].
Clinicians can focus on eliminating or minimizing the incidence of VAP through preventive techniques. While little has affected the incidence of late-onset VAP, the occurrence of early-onset VAP can be reduced by simple measures such as placing a patient, in a semi recumbent position. Yet, even apparently simple preventive measures are not easy to control: it was shown that health care team compliance rates is insufficient and varies between 30% and 64% [17]. The medical challenge of preventing contamination of the respiratory pathways by gastrointestinal reflux in ventilated patients is well known in the Art. Several technical solutions were proposed as it can be appreciated in the following brief review.
US 2008/0171963 relates to a device that prevent aspiration of gastric fluids in patients being fed or medicated through a gastric tube and placed in a semi-recumbent position. The device comprises an angle sensor fixed to said patient and an electrical control circuit which may stop the flow in the gastric tube if the patient is reclining beyond a predetermined angle, thereby decreasing the risks of aspiration. However, US 2008/0171963 is unsuitable in all the cases were the patient should be placed in supine position and not in semi-recumbent position.
WO 01/24860 relates to an artificial airway device comprising a laryngo-pharyngal mask including a roughly elliptical expandable masking ring. The expandable mask sealingly surrounding the laryngeal inlet when expanded to obstruct communication between the laryngeal inlet and esophagus to avoid reflux of gastric contents. A gastro-tube provides a fluid flow-path to the surface of the mask facing the esophagus when the mask sealingly surrounds the laryngeal inlet. However, this inflatable laryngo-pharyngal mask is blocking the natural flow of saliva from the oral cavity to the stomach. Moreover, laryngo-pharyngal masks cannot be applied for long periods of time as the pressure exerted on the esophagus sidewalls by the expandable element may cause irreversible damages on epithelial tissues.
WO 2009/027864 relates to an enteral feeding unit that helps to reduce the occurrence of gastro-esophageal-pharyngeal reflux during enteral feeding. The unit, comprises a gastric sensor placed within the stomach and a sealing element placed within the esophagus. When the gastric sensor reports a pressure increase into the stomach, the esophagus is sealed to avoid the reflux of gastric contents. However, complete sealing of the esophagus pathway may be problematic as it avoids deglutition of saliva, and reflux of accumulated saliva may be wrongly redirected into the airway system. Furthermore, long time appliance of high pressure on the esophagus sidewalls may cause severe damages to the epithelial tissues.
Therefore, there is a need for a device that is deployable by any trained caregiver personnel for the prevention or reduction of aspirations from the alimentary tract to the respiratory system.
It is therefore an object of the invention to provide a device which enables feeding a patient in need through an enteral route and which also prevents, or significantly reduces, gastro-esophageal reflux from the alimentary tract to the respiratory system.
It is another object of the invention to provide a device which enables feeding a patient in need through an enteral route and allow the swallowing of saliva, nasopharynx and oropharynx secretions.
It is a further object of the invention to provide a device which enables feeding a patient in need through an enteral route without damaging epithelial esophagus tissues.
It is a further object of the invention to provide a system which enables feeding a patient in need through an enteral route, and which can control and monitor the transit of fluids and biological secretions in the esophagus.
It is a further object of the invention to provide a method for significantly reducing vomiting events in an enterally fed patient.
It is a further object of the invention to provide a method for the insertion and the correct positioning of a feeding tube into the esophagus of a patient in need of enteral feeding.
Further purposes and advantages of this invention will appear as the description proceeds.